What Type Of Sealant Does Not Require The Presence Of Air To Cure?: The Ultimate Guide
Introduction to Air-Independent Curing Systems In high-precision industrial manufacturing, the reliance on atmospheric conditions for curing can lead to significant bottlenecks. Traditional sealants, such as Room Temperature Vulcanizing (RTV) silicones, often require moisture or oxygen to initiate the cross-linking process. However, in enclosed assemblies, deep-section potting, or vacuum-sealed environments, these traditional methods fail. The question of what type of sealant does not require the presence of air to cure is central to optimizing throughput in the aerospace, rail transit, and electronics sectors. The two primary categories of sealants that solve this challenge are anaerobic adhesives and radiation-curable (UV/Visible light) systems. Anaerobic Sealants: The Science of Deprivation Anaerobic sealants are unique thermoset resins that remain liquid in the presence of oxygen. The curing process is only triggered when the sealant is deprived of air and comes into contact with metal ions (typically iron or copper). This makes them the industry standard for thread-locking, flange sealing, and retaining applications where the bond line is compressed between two metallic surfaces. The Chemical Mechanism The polymerization of anaerobic sealants is based on methacrylate chemistry. When the sealant is confined between metal surfaces, the oxygen—which acts as a stabilizer—is excluded. In this oxygen-free environment, the metal ions on the substrate act as a catalyst to break down hydroperoxides, initiating a free-radical polymerization chain reaction. This results in a highly cross-linked, rigid plastic that provides exceptional vibration resistance and shear strength. UV and Visible Light Curing Sealants For applications where rapid assembly is required and substrates may not be metallic, UV and visible light-curing sealants are the premier choice. Unlike moisture-cure systems, these sealants utilize photo-initiators that respond to specific wavelengths of light (typically 365nm to 405nm) to initiate an instant cure. Because the energy source is external (light), no air or atmospheric moisture is required to complete the reaction. See UV glue vs epoxy for transparent bonding for how this curing pathway compares with two-part chemistries more broadly. Technical Features and Specifications Viscosity Range: Available from ultra-low (50 cPs) for capillary action to high-viscosity thixotropic gels (50,000+ cPs) for gap filling. Thermal Stability: Engineered to withstand operating temperatures from -55°C up to 200°C (-67°F to 392°F). Cure Speed: Achievement of full structural bond strength in 0.5 to 30 seconds, depending on light intensity and bond line depth. Shore Hardness: Options ranging from flexible elastomers (Shore A 40) to rigid structural resins (Shore D 85). Chemical Resistance: High resistance to hydrocarbons, water-glycol mixtures, and common industrial solvents. If you're unsure whether an anaerobic or a UV-curable chemistry fits your assembly geometry, Email Us and an applications engineer can walk through the substrate and fixturing details with you. Industrial Applications for Non-Airing Sealants Aerospace and Defense In aerospace engineering, anaerobic sealants are vital for securing fasteners in turbine engines and hydraulic systems. The high vibration environment requires a sealant that will not degrade or migrate. Furthermore, UV-curing maskants are used to protect sensitive components during turbine blade coating processes, where air is absent during vacuum deposition. Rail…